Three-phase oscillator



Patented Dec. 27, 1927.

UNITED STATES v 4,1 6 PATENT OFFICE.

ALBERT H. TAYLOR, OF WASHINGTON, DISTRICT OF CODUMIBIA, AS SIGNOR TO WIRED I RADIO, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

crrrnnn-rnesn oscrrraron.

Application filed November 30, 1925. Serial No. 72,411.

My invention relates broadly to the generation of three phase high frequency current and more particularly to'an electron tube circuit arrangement for the generation of three phase high frequency current with means for regulating the currents in the.

several phases of the high frequency system. One of the objects of my invention isto provide a simplified construction of electron tube generator of three phase high frequency current, where the current in the several phases is maintained in 120 degree phase relationship.

Another objectof my invention is to provide a delta connected three phase generator of high frequency current, in which one or more of the phases is controlled by constant frequency oscillators such as piezo electric crystals arranged in one or more of the phases for maintaining the currents of each of the phases at a 120 vdegree relationship. My invention provides a source'of three phase hi h frequency current which may be '25 utilized in the systems set forth in Letters,

Patent 1,560,505 dated November 3, 1925 and granted to Robert D. Duncan, Jr., andin the systems in co-pending application filedby Robert D. Duncan, J r., Serial No. 35,212, :0 filed June 5, 1925, which became patent 1,592,085, July 13, 1926, entitled Three phase wired radio recelving circuits; applicationv Serial No. 45,131, filed July 21, 1925, by

Robert 5). Duncan, Jr., for. Three hase as high frequency system; application erial No. 45,132 filed J uly' 21, 1925, by Robert D.

. Duncan, J r., Samuel Isler and Salvatore A. Barone, for Three phase high frequency system; and application Serial No. 45,948,.fi1ed x July 24, 19 25, which became-Patent 1,591,-

f 025, July 6, 1926, by Robert D. Duncan, J r.,

--for Duplex radio tele hone system. My invention will e more fully v stood by reference to the following specifi- 4.5 cation and the accompanying drawings, in

which: v

Figure 1 illustrates a delta connected elec. tron tube oscillator system in which the currents in the several hases are controlled "so by piezo electric crysta Fig. 2- illustrates a. modified arrangement of delta'connected oscillators in which currents for two of the phases are delivered by self-excited tube oscillators, while the three phase is controlled by a constant frequency piezo electricvcrys lati'ons.

under-- stantially noload. The output circuit of electron tube 1 includes condenser 9, and intal oscillator; and Fig. 3 is a vector diagram illustrating the angular displacement -three phase high frequency communication systems set forth in the aforementioned references. The three phase high frequency generator of the present invention ma be compactly constructed utilizing single p ase electron tube oscillators and integrating the currents in the several phases in a common output circuit from which may be derived the three phase current. In order to control the frequency of the three phase current, piezo electriccrystals are arranged in the input circuits of one or more of the tubes which form the single phase generators in each of the phases ofthe three phase system and the oscillators automatically fall into step and keep in synchronism at 120 degrees apart, thereby generating three phcse current in the delta connected circu1 4 Referring to the drawings in more detail reference characters 1, 2' and 3 represent electron tubes, each arranged in single phase oscillation circuits. Each tube is provided with grid, filament and plate, electrodes, which I have designated in the case of electron tube 1 by reference'chara'cters "1, 1 and 1. Each tube has an input and output circuit arranged for the generation of oscil The input circuit of tube 1 be-- tween grid electrode 1 and filament elec-. trode 1", is represented-at 4 containing a frequency determining. element or piezo electric crystal 5 in series with sensitizin' choke 6, which circuit is, shunted by a radio frequency choke coil 7 in series with a source of. negative potential 8, by which the piezo electric crystal oscillator is operated at subductance 10 tuned by variable condenser 11. The inductance 10' is coupled with inductance 12 in one side of a delta connected system designated at D. V

The second base is made up by the circuits of electron tube 2, the nput circuit 14 of which is completed through iezo elec-' tric crystal 15 and cho e 16, the contro circuit being shun by radio ire- 11.

quency choke 17 and source of negative potential 18. The output circuit of electron tube 2 includes inductance 19, and stopping 1 30. The inductance 28 is coupled with incondenser shunted by tuning condenser 21. Inductance 19 is coupled with inductance 22 of the delta connected system.

The three phase is formed by electron tube generator 3 having an input circuit 23 which is closed through constant frequencypiezo electric crystal oscillator 24 connected in series with sensitizing choke 25 and shunted by radio frequency choke 26 and source of negativepotential 27. ,The output circuit of electron, tube 3'includes inductance 28, stopping condenser'29 and tuning condenser 'ductance 31 in the delta connected system.

I have represented independent batteries for heating the electrodes of each of the electron tubes, in the separate phases, but it will'be understood that a common cathode heating battery may be employed for all of the tubes of the system. The various plate electrodes for all of the tubes are supplied with high potential from direct current source 32, through radio frequency choke coils 33, "34, and 35, with a returnelead to the several cathode circuits. The inductances 12, 22 and 31, in the delta connected system,-

impressed upon the delta connected circuit,

will cause a circulating current in the delta circuit, unless/the phases of the oscillators are angularly separated by 120' degrees, which .will result in drawing power out of certain of the tubes and the returning of power into others of the tubes. The result of this will be to advance the phase of one or more tubes tothe phase of such tubes as supply power- .for this circulating current in the delta. The tubes will, therefore, au-

tomatically adjust themselves to a normal f three phase relationship, 120 degrees apart.

Between'points A and B, between C and B, and C and A, voltages are therefore de-' ,veloped which are in three phase relationship, 120 degrees apart. Between these points, therefore, the load of any nature may be connected. Preferably before going to an antenna system or to a wire distributing system one or more stages of amplifica- -tion maybe provided, one set of amplifiers being between A and B, one between B and C, and one between A and CI The grids of these amplifiers would therefore be excited with threephase current in the proper phase 7 relationship.

- Thequartz or piezo electriccrystals 5, 15 and 24 are ground to the same frequency of oscillation and the'crystals soar-ranged in each of, the phases that the currents are maintained in phase with 120 degrees relationship, as represented in Fig. 3.

In some instances it is desirable that the frequency of one or more of the phases may shift above or below a pre-determined value fixed by the frequency of another phase, in

order to automatically adjust the normal three phase relationship of the several currents. Accordingly, in Fig. 2, I have shown electron tubes 2 and 3 arranged for self-excitation and the generation of oscillations without piezo electric crystal control, while the electron tube 1 is controlled by a piezo electric crystal. In this manner the piezo electric crystal 5 fixes the frequency of the system, 'while the arrangement of the delta connected tubes is such that the currents are spaced 120 degrees apart.

The three phase generator may work into a line wire system which I have designated iver the three phase energy to any suitable load. While I have shown only single electron tubes in each of the phases of the high frequency system, it will be understood that a- .multiplicity of tubes may be used and enerally by reference character 40 and de-,.

arranged to deliver their common output to the delta connected system.

\Vhile I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon the invention are intended other than are imposed by the scope of the appended clams.

high frequency oscil ations, t e combination-of three independent set-s of single phase oscillators, a common output circuit to which all of said oscillators are connected, and a mechanically vibratin element capable of sustaining constant equency oscillations connected with the input circuit of one of said oscillators for maintaining the currents generated by said three independent oscillators at'120 degreesphase displacement.

3. In a three phase system for the generation of high frequency currents, the combination of three independent sets of high said oscillators are delivered, at least two of said oscillators being capable of a. shift in What I claim and desire to secure by frequency oscillators, a common output c1rcult into which the oscillations from each of chanically vibratile element capable of susfrequency from a predetermined limit and a piezo electric crystal connectedin circuit with one of said independent oscillators for facilitating the maintenance of the hase-relationship of the currents delivere to said common output circuit .v e

4. A three phase high frequency oscillator comprising in combination a set of three independent electron tubes each having grid, filament and plate electrodes, input and output circuits interconnecting said electrodes, a delta connected circuit, connections between each of said output circuits and said delta connected circuit, and a 'metaining constant frequency oscillations connected in a selected one of said input circuits for controlling the output of each of said electron tubes for displacing the currents supplied to said delta connected circuit 120 degrees apart in phase. A 1

5. In a system for generating three phase high frequency current, the combination of a delta connected circuit, means for tuning 'each branch of said circuit, a set of three independent electron tubes each'having grid,

, filament .and plate electrodes, an output circuit, interconnecting said plate and filament electrodes, an input circuit intercon- Lnecting said grid and filament electrodes,

means couplingrthe out ut circuit of each of said electron tubes wit 'a tuned branch of said delta connected circuit, a constant frequency generator of oscillations connected in each branch of said circuit, a set of three independent electron. tubes each having grid,

filament and plate electrodes, an output circuit interconnecting said plate and filament electrodes, an input circuit interconnecting said grid and filament electrodes, means coupling the output circuit of each of said electron tubes with a tuned branch of said delta connected circuit, at least one of said electron tubes having its input and output circuits mutually coupled for sustaining oscillations shiftable in frequency above or below a predetermined limit, a piezo electric device connected in the input circuit of the other of said electron tubes for sustaining oscillations at said predetermined frequency limit in the circuits of said last mentioned electron tubewhereby the currents in said delta-con V nected circuit are automatically adjusted in phase through an angular displacement of 120 degrees.

p ALBERT H.- TAYLOR, 

